The present invention relates generally to electro-optic chromophore bridge compounds and donor-bridge compounds which can be used in the preparation of chromophores for use in polymeric thin films for waveguide media, and specifically to organic nonlinear chromophore bridge compounds and donor-bridge compounds for polymeric switches and modulators.
Thin films of organic or polymeric materials with large second order nonlinearities in combination with silicon-based electronic circuitry can be used in systems for laser modulation and deflection, information control in optical circuitry, as well as in numerous other waveguide applications. In addition, novel processes through third order nonlinearity such as degenerate four-wave mixing, whereby real-time processing of optical fields occurs, have utility in such diverse fields as optical communications and integrated circuit fabrication. The utility of organic materials with large second order and third order nonlinearities for very high frequency applications contrasts with the bandwidth limitations of conventional inorganic electro-optic materials currently in use.
Numerous optically responsive monomers and polymers have been developed for use in organic materials which, in turn, can be used in the waveguide applications described above. For example, U.S. Pat. No. 5,044,725, which is incorporated herein by reference in its entirety, describes numerous polymer compositions which provide suitable nonlinear optical response. U.S. Pat. No. 5,044,725 describes, for example, a preferred polymer composition comprising an organic structure containing an electron donating group and an electron withdrawing group at opposing termini of a bridge.
Synthesis of high performance organic, high xcexcxcex2 electro-optic chromophores must be accomplished in order to make polymer-based electro-optic devices. The synthesis of electro-optic chromophore bridge compounds and donor-bridge compounds for organic nonlinear optical applications is generally known in the art. Although some bridge compounds and donor-bridge compounds have been reported in the literature, many of them have showed several and sometimes severe problems ranging from thermal instability, insolubility in the polymer, photodegradability, exhibition of a broad absorption band into the wavelength region of interest, and large birefringence upon poling. Accordingly, suitable electro-optic chromophore bridge compounds and donor-bridge compounds are desired.
The present invention is directed to compounds which can serve as electro-optic chromophore bridge compounds for use in, for example, thin polymer films for waveguides. Preferred bridge compounds of the invention have Formula I. 
Preferably, K is O or S. Preferably, R1 is xe2x80x94Qxe2x80x94CnH2n+1, xe2x80x94Qxe2x80x94(CH2)aCnF2n+1, xe2x80x94Qxe2x80x94CH2SCH2CnF2+1, or xe2x80x94Qxe2x80x94CH2SCH2CF3, where n is 1-10 and a is 0-10, or xe2x80x94Qxe2x80x94CH2OCH2CF3. Other halogens or deuterium can be used in place of F. Q preferably is either absent or, when present, O or S. X preferably has the formula H or xe2x80x94(CHxe2x95x90CH)bC(xe2x95x90O)H, where b is 0-3. Z is a chemical group that is capable of being linked to a donor and includes, but is not limited to, Br, I, xe2x80x94CH2xe2x80x94Br, xe2x80x94CH2xe2x80x94OH, xe2x80x94CH3, xe2x80x94C(xe2x95x90O)H, xe2x80x94(CHxe2x95x90CH2)n where n is 1-3, and the like. Those skilled in the art can use additional groups known to those skilled in the art to couple a bridge compound to a donor. Another Z group that can used to link a bridge compound to a donor is 
where Yxe2x88x92 is a counter ion.
Other preferred bridge compounds of the invention have Formula II. 
G is preferably xe2x80x94Cxe2x95x90Cxe2x80x94Cxe2x95x90Cxe2x80x94. X preferably is H or xe2x95x90CH(xe2x80x94CHxe2x95x90CH)dxe2x80x94C(xe2x95x90O)H, where d is 0-3.
Other preferred bridge compounds of the invention have Formula III. 
Preferably, J is CH2, O or S. Preferably, R1 is xe2x80x94Qxe2x80x94CnH2+1, xe2x80x94Qxe2x80x94(CH2)aCnF2n+1, xe2x80x94Qxe2x80x94CH2SCH2CnF2n+1, or xe2x80x94Qxe2x80x94CH2SCH2CF3, where n is 1-10 and a is 0-10, or xe2x80x94Qxe2x80x94CH2OCH2CF3. Other halogens or deuterium can be used in place of F. Q preferably is either absent or, when present, O or S. X preferably has the formula (Cxe2x95x90O)H, or Cxe2x95x90CH(xe2x80x94CHxe2x95x90CH)dxe2x80x94C(xe2x95x90O)H, where d is 0-3. Z is a chemical group that is capable of being linked to a donor and includes, but is not limited to, xe2x80x94CH2xe2x80x94Br, xe2x80x94CH2xe2x80x94OH, xe2x80x94CH3, xe2x80x94C(xe2x95x90O)H, Br, I, and the like. Those skilled in the art can use additional groups known to those skilled in the art to couple a bridge compound to a donor. Another Z group that can be used to link a bridge compound to a donor is 
where Yxe2x88x92 is a counter ion.
The present invention is also directed to compounds which can serve as electro-optic chromophore donor-bridge compounds for use in, for example, thin polymer films for waveguides.
Preferred donor-bridge compounds of the invention have Formula IV. 
Preferably, K is O or S. D is preferably an electron donating group. Preferably, R1 is xe2x80x94Qxe2x80x94CnH2+1, xe2x80x94Qxe2x80x94(CH2)aCnF2n+1, xe2x80x94Qxe2x80x94CH2SCH2CnF2n+1, or xe2x80x94Qxe2x80x94CH2SCH2CF3, where n is 1-10 and a is 0-10, or xe2x80x94Qxe2x80x94CH2OCH2CF3. Other halogens or deuterium can be used in place of F. Q preferably is either absent or, when present, O or S. X preferably has the formula H or (xe2x80x94CHxe2x95x90CH)bxe2x80x94C(xe2x95x90O)H, where b is 0-3. Preferably, q is 1, 2, or 3.
Other preferred donor-bridge compounds of the invention have Formula V. 
Preferably, R1 is H, xe2x80x94Qxe2x80x94CH2+1, xe2x80x94Qxe2x80x94(CH2)aCnF2n+1, xe2x80x94Qxe2x80x94CH2SCH2CnF2n+1, or xe2x80x94Qxe2x80x94CH2SCH2CF3, where n is 1-10 and a is 0-10, or xe2x80x94Qxe2x80x94CH2OCH2CF3. Other halogens or deuterium can be used in place of F. Q preferably is either absent or, when present, O or S. D is preferably an electron donating group. X preferably has the formula (xe2x95x90O), or xe2x95x90CH(xe2x80x94CHxe2x95x90CH)dxe2x80x94C(xe2x95x90O)H, where d is 0-3. R2 and R3 each, independently, are preferably CnH2n+1 where n is 2-10.
Other preferred donor-bridge compounds of the invention have Formula VI. 
Preferably, J is CH2, O or S. Preferably, R1 is xe2x80x94Qxe2x80x94CnH2n+1, xe2x80x94Qxe2x80x94(CH2)aCnF2n+1, xe2x80x94Qxe2x80x94CH2SCH2CnF2n+1, or xe2x80x94Qxe2x80x94CH2SCH2CF3, where n is 1-10 and a is 0-10, or xe2x80x94Qxe2x80x94CH2OCH2CF3. Other halogens or deuterium can be used in place of F. Q preferably is either absent or, when present, O or S. D is preferably an electron donating group. X preferably has the formula (Cxe2x95x90O)H, or Cxe2x95x90CH(xe2x80x94CHxe2x95x90CH)dxe2x80x94C(xe2x95x90O)H, where d is 0-3.
The present invention relates, in part, to novel electro-optic chromophore bridge compounds and donor-bridge compounds which have utility in organic nonlinear optical applications. Electro-optic chromophores comprising the donor-bridge compounds of the invention exhibit thermal stability to temperatures from 260xc2x0 C. to 310xc2x0 C. Chromophores comprising the donor-bridge compounds of the invention also show great solubility in most common organic solvents and, thus, are useful in most polymer films for waveguides. In addition, under intense UV-irradiation (365 nm, dosage 3 J/cm2 up to 13 minutes), the chromophores comprising the donor-bridge compounds of the invention show no changes of UV-VIS-NIR spectrum, which indicates that the chromophores are, to a major extent, photo stable.
The compounds of the invention can be used in, for example, polymeric organic materials for optical waveguides. Such polymeric organic materials are described in, for example, U.S. Pat. Nos. 5,044,725, 4,795,664, 5,247,042, 5,196,509, 4,810,338, 4,936,645, 4,767,169, 5,326,661, 5,187,234, 5,170,461, 5,133,037, 5,106,211, and 5,006,285, each of which is incorporated herein by reference in its entirety.
The phrase xe2x80x9celectron donating groupxe2x80x9d is used synonymously with xe2x80x9celectron donatorxe2x80x9d and refers to substituents which contribute electron density to the xcfx80-electron system when the conjugated electron structure is polarized by the input of electromagnetic energy.
The phrase xe2x80x9cdonor-bridge compoundxe2x80x9d refers to an electron donating group coupled to a bridge compound of the invention.
In preferred embodiments of the invention, the electro-optic chromophore bridge compounds comprise Formula I: 
Preferably, K is O or S.
Preferably, R1 is xe2x80x94Qxe2x80x94CnH2n+1, xe2x80x94Qxe2x80x94(CH2)aCnF2n+1, xe2x80x94Qxe2x80x94CH2SCH2CnF2n+1, or xe2x80x94Qxe2x80x94CH2SCH2CF3, where n is 1-10 and a is 0-10, or xe2x80x94Qxe2x80x94CH2OCH2CF3. Other halogens or deuterium can be used in place of F. Q preferably is either absent or, when present, O or S. By modification of the substituents on the bridge compound, fluorinated or deuterated alkyl groups can replace the hydrocarbon substituents and can make the chromophore compounds comprising the bridge compounds more compatible with highly halogenated low loss polymers.
In more preferred embodiments of the invention, a is 1-3 and n is 1-10. In more preferred embodiments of the invention, R1 is C1-C10, more preferably C4-C10, and may contain fluorine substitutions.
X preferably has the formula H or xe2x80x94(CHxe2x95x90CH)b-C(xe2x95x90O)H, where b is 0-3. Most preferably, b is 0-2. The terminal aldehyde group serves as the preferred site of reaction with electron withdrawing groups. In more preferred embodiments of the invention, b is O so that X is xe2x80x94C(xe2x95x90O)H.
Z is a chemical group that is capable of being linked to the donor and includes, but is not limited to, Br, I, xe2x80x94CH2xe2x80x94Br, xe2x80x94CH2xe2x80x94OH, xe2x80x94CH3, xe2x80x94C(xe2x95x90O)H, xe2x80x94(CHxe2x95x90CH2)n where n is 1xe2x80x943, and the like. Those skilled in the art can use additional groups known to those skilled in the art to couple a bridge compound to a donor. Another Z group that can be used to the link a bridge compound to a donor is: 
where Yxe2x88x92 is a counter ion including, but not limited to, Brxe2x88x92, Ixe2x88x92, or Crxe2x88x92.
In addition, the thiophene ring can also be substituted at the open position (3xe2x80x2) with, for example, an R1 moiety as described above. Further, the Bu groups can be substituted by, for example, phenyl groups.
In other preferred embodiments of the invention, the electro-optic chromophore bridge compounds comprise Formula II: 
G is preferably xe2x80x94Cxe2x95x90Cxe2x80x94Cxe2x95x90Cxe2x80x94. X preferably is H or xe2x95x90CH(xe2x80x94CHxe2x95x90CH)dxe2x80x94C(xe2x95x90O)H, where d is 0-3. In more preferred embodiments of the invention, X is (xe2x95x90O).
In other preferred embodiments of the invention, the electro-optic chromophore bridge compounds comprise Formula III: 
Preferably, J is CH2, O or S.
Preferably, R1 is xe2x80x94Qxe2x80x94CnH2n+1, xe2x80x94Qxe2x80x94(CH2)aCnF2n+1, xe2x80x94Qxe2x80x94CH2SCH2CnF2n+1, or xe2x80x94Qxe2x80x94CH2SCH2CF3, where n is 1-10 and a is 0-10, or xe2x80x94Qxe2x80x94CH2OCH2CF3. Other halogens or deuterium can be used in place of F. Q preferably is either absent or, when present, C or S. In more preferred embodiments of the invention, a is 1-3 and n is 1-3. In more preferred embodiments of the invention, R is C1-C10, more preferably C4-C10, and may contain fluorine substitutions.
X preferably has the formula (Cxe2x95x90O)H, or Cxe2x95x90CH(xe2x80x94CHxe2x95x90CH)dxe2x80x94C(xe2x95x90O)H, where d is 0-3. In more preferred embodiments of the invention, X is C(xe2x95x90O)H.
Z is a chemical group that is capable of being linked to a donor and includes, but is not limited to, Br, I, xe2x80x94CH2xe2x80x94Br, xe2x80x94CH2xe2x80x94OH, xe2x80x94CH3, xe2x80x94C(xe2x95x90O)H, xe2x80x94(CHxe2x95x90CH2)n where n is 1-3, and the like. Those skilled in the art can use additional groups known to those skilled in the art to couple a bridge compound to a donor. Another Z group that can be used to link a bridge compound to a donor is: 
where Yxe2x88x92 is a counter ion including, but not limited to, Brxe2x88x92, Ixe2x88x92, or Clxe2x88x92.
In other embodiments of the invention, the electro-optic chromophore bridge compound is coupled to an electron donating group to form an electro-optic chromophore donor bridge compound. In some preferred embodiments of the invention, the donor-bridge compounds comprise Formula IV. 
In Formula IV, a bridge compound having Formula I is coupled to an electron donating group D. Preferred electron donating groups include, but are not limited to, a phenyl ring substituted in the para position by, for example, amino, alkylamino, dialkylamino, 1-piperidino, 1-piperazino, 1-pyrrolidino, acylamino, hydroxyl, thiolo, alkylthio, arylthio, alkoxy, aryloxy, acyloxy, 1,2,3,4-tetrahydroquinolinyl, and the like.
Preferably, K is O or S.
Preferably, R1 is xe2x80x94Qxe2x80x94CnH2n+1, xe2x80x94Qxe2x80x94(CH2)aCnF2n+1, xe2x80x94Qxe2x80x94CH2SCH2CnF2n+1, or xe2x80x94Qxe2x80x94CH2SCH2CF3, where n is 1-10 and a is 0-10, or xe2x80x94Qxe2x80x94CH2OCH2CF3. Other halogens or deuterium can be used in place of F. Q preferably is either absent or, when present, O or S. By modification of the substituents on the bridge compound, fluorinated or deuterated alkyl groups can replace the hydrocarbon substituents and can make the chromophore compounds comprising the bridge compounds more compatible with highly halogenated low loss polymers. In more preferred embodiments of the invention, a is 1-3 and n is 1-10. In more preferred embodiments of the invention, R1 is C1-C10, more preferably C4-C10, and may contain fluorine substitutions.
X preferably has the formula H or xe2x80x94(CHxe2x95x90CH)bxe2x80x94C(xe2x95x90O)H, where b is 0-3. Most preferably, b is 0-2. The terminal aldehyde group serves as the preferred site of reaction with electron withdrawing groups. In more preferred embodiments of the invention, b is 0 so that X is xe2x80x94C(xe2x95x90O)H.
Most preferably, electron donating group D couples with a bridge compound having Formula I to produce a donor-bridge compound having Formula VII. 
In other preferred embodiments of the invention, the donor-bridge compounds comprise Formula V. 
In Formula VI, a bridge compound having the depicted formula is coupled to an electron donating group D. Preferred electron donating groups include, but are not limited to, a phenyl ring substituted in the para position by, for example, amino, alkylamino, dialkylamino, 1-piperidino, 1-piperazino, 1-pyrrolidino, acylamino, hydroxyl, thiolo, alkylthio, arylthio, alkoxy, aryloxy, acyloxy, 1,2,3,4-tetrahydroquinolinyl, and the like.
Preferably, R1 is H, xe2x80x94Qxe2x80x94CnH2n+1, xe2x80x94Qxe2x80x94(CH2)aCnF2n+1, xe2x80x94Qxe2x80x94CH2SCH2CnF2n+1, or xe2x80x94Qxe2x80x94CH2SCH2CF3, where n is 1-10 and a is 0-10, or xe2x80x94Qxe2x80x94CH2OCH2CF3. Other halogens or deuterium can be used in place of F. Q preferably is either absent or, when present, O or S.
X preferably has the formula (xe2x95x90O), or xe2x95x90CH(xe2x80x94CHxe2x95x90CH)dxe2x80x94C(xe2x95x90O)H, where d is 0-3. R2 and R3 each, independently, are preferably C1, C2 or C3 alkyl.
Most preferably, electron donating group D couples with a bridge compound to produce a donor-bridge compound having Formula VIII. 
In other preferred embodiments of the invention, the donor-bridge compounds comprise Formula VI. 
In Formula VI, a bridge compound having Formula III is coupled to an electron donating group D. Preferred electron donating groups include, but are not limited to, a phenyl ring substituted at the para position by, for example, amino, alkylamino, dialkylamino, 1-piperidino, 1-piperazino, 1-pyrrolidino, acylamino, hydroxyl, thiolo, alkylthio, arylthio, alkoxy, aryloxy, acyloxy, 1,2,3,4-tetrahydroquinolinyl, and the like.
Preferably, J is CH2, O or S.
Preferably, R1 is xe2x80x94Qxe2x80x94CnH2n+1, xe2x80x94Qxe2x80x94(CH2)aCnF2n+1, xe2x80x94Qxe2x80x94CH2SCH2CnF2n+1, or xe2x80x94Qxe2x80x94CH2SCH2CF3, where n is 1-10 and a is 0-10, or xe2x80x94Qxe2x80x94CH2OCH2CF3. Other halogens or deuterium can be used in place of F. Q preferably is either absent or, when present, O or S.
X preferably has the formula (Cxe2x95x90O)H, or Cxe2x95x90CH(xe2x80x94CHxe2x95x90CH)dxe2x80x94C(xe2x95x90O)H, where d is 0-3.
Most preferably, electron donating group D couples with a bridge compound having Formula III to produce a donor-bridge compound having Formula IX. 
The invention is further illustrated by way of the following examples which are intended to elucidate the invention. These examples are not intended, nor are they to be construed, as limiting the scope of the disclosure.